Small crack in screed but cant change level of floor what can we do

[Ajax123]

just got back from work and some really good stuff from you all. thanks so much. To summarise. we now need to put down some sort of matting down. The thinner the better. If the height of this is to much for the exsisting flooring can this height be lost over the size of the floor. 6m x 4.5m. Wish we could get the floor ripped up and started again. We trusted the builder as he said he could do the job but know wish we got somebody that knew what they were actually doing. thanks again.

NO need to rip it up. The crack can be repaired by using a simpl low viscosity epoxy resin to fillet. Then use an uncoupling membrane before tiling. Jobs a goodun

 

[Tim@Larsen]

Just to add my tuppence worth, I agree with everything Ajax has said. There should be no reason to rip the screed out if it is sound. However, it is important to be sure that it has 'finished' cracking before carrying out the crack injection. If you repair the crack too early you may find another crack appearing elswhere in the floor.

Once the floor has been repaired there should be no issue tiling onto it, but a decoupling mat would be belt and braces to be safe.

Cement based screeds are perfectly ok for use with underfloor heating, the problem is that the screed is typically around 75-100mm deep and so takes a long time to fully dry out, if the heat is turned on too early the screed is force-dried and they don't have the same tensile strength as gypsum screeds so are much more at risk of cracking. That said, it does seem like your builder was trying to do thngs right!